Causes of Tingling and Numbness – Paresthesia

What Does Tingling, Numbness and Paresthesia Mean?

Paresthesia (Greek para- = abnormal, esthesia = feeling) is abnormal sensation on the skin that has no apparent physical cause (1). Paresthesia includes numbness and tingling, and can be temporary or permanent.

Numbness is a decreased or lost sensation in the skin. Tingling is an unusual sensation in the skin. It is often described as feeling of pins and needles, tickling, pricking, creeping, skin crawling, ant crawling, and so on.

In certain disorders, like restless leg syndrome, tingling, numbness, burning, itchiness and pain may appear simultaneously.

Paresthesia can appear in any part of the body: in the trunk, limbs, fingers, toes, face or head.

Paresthesia and Dermatomes

Sensations are felt and interpreted by the brain. Sensibility of the trunk, limbs and the back of the head is mediated by the spinal nerves, arising from the spinal cord, and sensitivity of the face by Trigeminal nerve (5th cranial nerve), arising from the brainstem. The skin area innervated by a single nerve root of the spinal or Trigeminal nerve is called a dermatome (Latin derma = skin, tome = section), (Picture 1). From the distribution of abnormal skin sensations among dermatomes, a doctor can determine which nerves are affected.

Picture 1. Dermatomes in a human

Symptoms of Paresthesia

Paresthesia appears without warning, is usually painless, and can be felt as tingling or numbness. Sensitivity of the affected skin part can be increased, but it is usually decreased. Other symptoms, like pain, muscular weakness, cramps, abnormal reflexes, warmth or cool feeling, paleness, redness, swelling or rash may be present, depending on the nature of an underlying disease.

Tingling is sometimes incorrectly described as itchiness. Itchiness provokes desire to scratch, while tingling does not. Burning  is also not the same as tingling, but rather a form of pain.

We often say our arm or leg has fallen asleep, when it becomes temporarily paralysed and numb.

How Does Paresthesia Occur?

Sensations from the skin are carried from the skin via peripheral sensory nerves through the spinal cord, or via Trigeminal nerve and brain stem to the brain. Disorder at any level of these neural pathways can cause paresthesia.

Causes of Transient Paresthesia

Transient paresthesia, lasting from few seconds to several minutes, often described as feeling of ‘pins and needles’, may be due to:

• Obdormition – numbness caused by prolonged pressure on the nerve, like when you cross your legs and leg falls asleep. Such paresthesia disappears gradually as the pressure is relieved.
• Whiplash
• Hyperventilation syndrome
• Panic attack
• Dehydration
• Transient ischemic attack (TIA), sometimes referred as “mini stroke”
• Beta-alanine ingestion
• Seizures
• Raynaud phenomenon
• Insufficient blood supply in atherosclerotic arteries in the legs (in Burger disease, paresthesia is accompanied with calf pain)

Causes of Chronic Paresthesia

Long lasting or recurring paresthesia can arise from:

• Brain, spinal cord or peripheral nerve disorders: trauma, stroke, intra-cerebral hemorrhage, multiple sclerosis, tumors, encephalitis, meningitis, herniated disc, cervical spondylosis, pressure on the nerve (carpal tunnel syndrome, sciatica), repetitive motion or prolonged vibration, neuralgia
• Circulatory (heart and vessels) disorders: angina pectoris, atherosclerosis, acute arterial occlusion, vasculitis, Raynaud disease, vertebrobasilar circulatory disorders
• Metabolic and hormonal disorders: diabetes, low blood sugar (hypoglycemia), hypothyroidism, hypoparathyroidism, hypoaldosteronism (Conn syndrome), menopause, abnormal blood levels of calcium, potassium or sodium, uremia, porphyria
• Infections and post-infection syndromes: infection with Herpes simplex virus, Herpes zoster virus, arbovirus; canker sores, Lyme disease, AIDS (HIV), leprosy, Guillain-Barré syndrome, rabies, syphilis
• Connective tissue and autoimmune diseases: rheumatoid arthritis, systemic lupus erythematosus (SLE), Sjögren’s syndrome, pernicious anemia, diabetes
• Blood disorders: thrombosis, polycythemia, thrombocytosis, leukemia
• Bones and joints disorders: arthritis, osteomalacia, osteoporosis
• Fibromyalgia
• Nutrient deficiency: vitamin B1 deficiency (beriberi), vitamin B5 and B12 deficiency
• Malignancies
• Skin disorders: burns, frostbite, Ito syndrome, acrodynia, acroparesthesia
• Migraine
• Psychological disorders: anxiety, panic attack, psychiatric disease
• Medications: anti-convulsant drugs, lomotil, SSRI withdrawal, amiodarone, colistimethate, digoxin, dimercaprol, mefloquine, riluzole , tetrodotoxin, thallium, topiramate, overdose of lidocain or vit B6
• Alcohol, tobacco, illegal drugs
• Poisoning: heavy metals (arzenic, lead, mercury), long term exposure to nitrous oxide, carbon monoxide, ciguatera poisoning, snake bites
• Radiation exposure, chemotherapy
• Hereditary diseases: Refsum syndrome, Fabry disease, Charcot-Marie-Tooth disease (a hereditary disorder that causes wasting of the leg muscles), porphyria, Denny-Brown’s syndrome (a hereditary disorder of the nerve root), ataxia-teleangiectasia
• Immune deficiency

Diagnosis of the Cause of Paresthesia

1. Before appointment with your doctor, answer the following questions:

• On which parts of your body do you feel tingling or numbness,  and is it limited to one side of the body (left or right)? How would you describe the felling: like numbness, loss of sensation, pricking, creeping, burning, itching, pins and needles…?
• When did unusual sensation appear, is it permanent or transient? Does sensation change throughout the day?
• What triggers the sensation: warmth, exercise, sitting, stress, food, medications…?
• Other symptoms in the affected body part: pain, paleness, redness, swelling, warmth, coolness, cramps, loss of muscular power?
• Any other general symptoms, like fever or headache?
• Do you have any chronic disease, like diabetes or rheumatoid arthritis? Were you injured or admitted to the hospital in the past from some reason? Which diagnose(s) you have or had so far?
• Does your work require repetitive motion, are you affected by constant vibrations, or exposed to certain chemicals like nitrogen oxide or carbon monoxide?
• Are you under stress, are you anxious?
• What is your diet, do you drink alcohol or smoke, which medications or drugs are you taking?

2. Doctor will examine you, what includes detailed neurological examination.

3. Doctor may order the following tests:

• MRI or CT of the head and/or spine
• MRI, CT or X-ray of the chest, abdomen, bones or joints
• Blood tests: CBC, sedimentation rate, electrolytes, vitamins, sugar, sedimentation rate (ESR), proteins, thyroid hormones, heavy metals, drugs, antibodies to certain microbes, etc.
• Urine tests: glucose, proteins, etc.
• Electromyography (EMG), nerve conduction tests
• Lumbar puncture (only when central nervous system disorders, like multiple sclerosis or meningitis, are suspected)
• Vascular ultrasound and a cold stimulation test to check for Raynaud’s phenomenon
• Nerve biopsy (rarely)

Treatment of Paresthesia

Treatment of paresthesia depends on the cause. Paresthesia is usually treated by a neurologist.

Home Care

Numbness after prolonged sitting or uncomfortable body position usually goes away after restoring circulation by stretching or massaging the affected limb. If the underlying cause cannot be treated, aspirin or ibuprofen can be tried. In more difficult cases, low dose of antidepressant drugs, such as amitriptyline, are sometimes prescribed to alter body’s perception of pain. In severe cases, opiates, as codeine, can be prescribed (3).

In nutritional deficiency, supplements, like B complex vitamins, especially vitamin B 12, can be tried (3).

Alcohol should be avoided. Self-massage with aromatic oils or ointments containing capsaicin may give temporary relief. Wearing lose shoes, gloves and clothes may also be helpful (3).

Call Emergency if you:

• Feel weak, walk difficulty, hardly move an arm, have problems with speech or vision
• Can not control your bladder or bowel
• Feel numbness after an injury
• Have lost consciousness, even if only for a while

Call your Doctor if you:

• Do not know what causes abnormal sensations
• Find out that numbness worsen during walking (could be pinched sciatic nerve)
• Have pain, cramps, dizziness
• Are urinating more often (could be diabetes)
• Developed a rash you can not explain

Prognosis of Paresthesia

There is no known long-term physical effect from paresthesia itself (2). A disorder causing paresthesia can lead to permanent nerve damage, so this is why you need to visit a doctor, when the cause is uncertain. Prognosis depends on the underlying cause.

Related Articles:

• Numbness of Head, Face and Neck
• Tingling and Numbness in Arm, Hand and Fingers
• Numb Feet and Toes
• Numbness in Both Hands and Feet
• Itchy Skin – Causes
• Itchy Face, Facial Rash
• Types of Skin Rashes

References:

1. Paresthesia Definition (medterms.com)
2. Disorders of a Single Peripheral Nerve and Numbness  (merck.com)
3. Causes of Paresthesia (wrongdiagnosis.com)
4. Diagnosis of Paresthesia  (wrongdiagnosis.com)